Earlier quoted context omitted.
When I was in high school, almost everyone used AIM. Then Facebook Chat came out and practically crushed it. Why? It wasn't better (it was far, far, worse, actually — you couldn't chat with somebody without one of you complaining about it), but everyone was there . It became the defacto way to reach people. It was successful for the same reason Facebook was successful.
Maybe it's just me, but there seems to be a 10 year gap in your IM technology timeline there. AIM straight to Facebook? Was I the only one using ICQ, MSN, Google Chat before Facebook came along?
I don't know, was you the only person on that service and thus have no-one to talk to?